The boost stage is a centrifugal-type pump. The main stage is a gear-type pump. The above sentence means "增压级泵是一个齿轮式泵,主要级泵是一个离心式泵."
A.1正确答案B
The boost stage is a centrifugal-type pump. The main stage is a gear-type pump. The above sentence means "增压级泵是一个齿轮式泵,主要级泵是一个离心式泵."
A.1正确答案B